[Evaluation of fatty liver changes and fatty degeneration in liver tumors by 1H-MRS].

This study assesses the ability of 1H-MR spectroscopy (MRS) to evaluate fatty liver changes and fatty degeneration in liver tumors using the STEAM sequence, 1 cm3 VOI, TR/TE/excitations = 600/34/32, during breath-holding. To determine the correlation between lipid group signal ratio (fat fraction (FF)) obtained from in vivo 1H-MRS studies and liver lipid obtained from in vitro measurements (Folch method), an experimental fatty liver model in rabbits was used. Excellent correlation between them (R = 0.94) was noted. The result suggest that fatty liver (over 5% lipid accumulation by weight) is present when the FF by MRS is greater than 3.6%. Thirty-seven liver parenchymal and 18 hepatic tumors (17 hepatocellular carcinomas and 1 cholangiocellular carcinoma) with histological confirmation of the lipid content in 39 patients were examined to assess the clinical utility. Histological fat content was classified into grades 0-4 according to Levinson et al. There was a high correlation between MRS and histology in groups 0 to 2. MRS had a sensitivity of 100%, a specificity of 83% and an accuracy of 86% for diagnosis of "fatty liver" compared to histologic data, whereas CT had a sensitivity of 43%, a specificity of 90%, and an accuracy of 81%. MRS with STEAM sequence appears to be useful method in diagnosis of fatty liver with high sensitivity and accuracy, which is obtained in short time (approximately 7 minutes) and without ionizing radiation exposure.